app.py

import os
import time
import streamlit as st
from twilio.rest import Client
from pdfminer.high_level import extract_text
from sentence_transformers import SentenceTransformer
from transformers import AutoTokenizer
import faiss
import numpy as np
import docx
from groq import Groq
import PyPDF2
import requests
from streamlit_autorefresh import st_autorefresh

# Extract text from PDF with fallback
# --- Document Loaders ---
def extract_text_from_pdf(pdf_path):
    try:
        text = ""
        with open(pdf_path, 'rb') as file:
            pdf_reader = PyPDF2.PdfReader(file)
            for page_num in range(len(pdf_reader.pages)):
                page = pdf_reader.pages[page_num]
                page_text = page.extract_text()
                if page_text:
                    text += page_text
        return text
    except:
        return extract_text(pdf_path)

def extract_text_from_docx(docx_path):
    try:
        doc = docx.Document(docx_path)
        return '\n'.join(para.text for para in doc.paragraphs)
    except:
        return ""

def chunk_text(text, tokenizer, chunk_size=150, chunk_overlap=30):
    tokens = tokenizer.tokenize(text)
    chunks, start = [], 0
    while start < len(tokens):
        end = min(start + chunk_size, len(tokens))
        chunk_tokens = tokens[start:end]
        chunks.append(tokenizer.convert_tokens_to_string(chunk_tokens))
        start += chunk_size - chunk_overlap
    return chunks

def retrieve_chunks(question, index, embed_model, text_chunks, k=3):
    question_embedding = embed_model.encode([question])[0]
    D, I = index.search(np.array([question_embedding]), k)
    return [text_chunks[i] for i in I[0]]

# Generate answer using Groq API with retries and timeout
def generate_answer_with_groq(question, context, retries=3, delay=2):
    url = "https://api.groq.com/openai/v1/chat/completions"
    api_key = os.environ.get("GROQ_API_KEY")
    if not api_key:
        return "⚠️ GROQ_API_KEY not set."

    headers = {
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    }
    prompt = (
        f"Customer asked: '{question}'\n\n"
        f"Here is the relevant product or policy info to help:\n{context}\n\n"
        f"Respond in a friendly and helpful tone as a toy shop support agent."
    )
    payload = {
        "model": "llama3-8b-8192",
        "messages": [
            {
                "role": "system",
                "content": (
                    "You are ToyBot, a friendly and helpful WhatsApp assistant for an online toy shop. "
                    "Your goal is to politely answer customer questions, help them choose the right toys, "
                    "provide order or delivery information, explain return policies, and guide them through purchases. "
                    "Always sound warm, helpful, and trustworthy like a professional customer support agent."
                )
            },
            {"role": "user", "content": prompt},
        ],
        "temperature": 0.5,
        "max_tokens": 300,
    }

    for attempt in range(retries):
        try:
            response = requests.post(url, headers=headers, json=payload, timeout=10)
            response.raise_for_status()
            result = response.json()
            return result['choices'][0]['message']['content'].strip()
        except requests.exceptions.HTTPError as e:
            if response.status_code == 503 and attempt < retries - 1:
                time.sleep(delay)
                continue
            else:
                return f"⚠️ Groq API HTTPError: {e}"
        except Exception as e:
            return f"⚠️ Groq API Error: {e}"

# Twilio message fetch and send
def fetch_latest_incoming_message(account_sid, auth_token, conversation_sid):
    client = Client(account_sid, auth_token)
    messages = client.conversations.v1.conversations(conversation_sid).messages.list(limit=10)
    for msg in reversed(messages):
        if msg.author.startswith("whatsapp:"):
            return msg.body, msg.author, msg.index
    return None, None, None

def send_twilio_message(account_sid, auth_token, conversation_sid, body):
    try:
        client = Client(account_sid, auth_token)
        message = client.conversations.v1.conversations(conversation_sid).messages.create(author="system", body=body)
        return message.sid
    except Exception as e:
        return str(e)

# Streamlit UI
st.set_page_config(page_title="Quasa – A Smart WhatsApp Chatbot", layout="wide")
st.title("📱 Quasa – A Smart WhatsApp Chatbot")

if "last_index" not in st.session_state:
    st.session_state.last_index = -1

account_sid = st.secrets.get("TWILIO_SID")
auth_token = st.secrets.get("TWILIO_TOKEN")
GROQ_API_KEY = st.secrets.get("GROQ_API_KEY")

if not all([account_sid, auth_token, GROQ_API_KEY]):
    st.warning("⚠️ Some secrets not found. Please enter missing credentials below:")
    account_sid = st.text_input("Twilio SID", value=account_sid or "")
    auth_token = st.text_input("Twilio Auth Token", type="password", value=auth_token or "")
    GROQ_API_KEY = st.text_input("GROQ API Key", type="password", value=GROQ_API_KEY or "")

enable_autorefresh = st.checkbox("🔄 Enable Auto-Refresh", value=True)
interval_seconds = st.selectbox("Refresh Interval (seconds)", options=[5, 10, 15, 30, 60], index=4)

if enable_autorefresh:
    st_autorefresh(interval=interval_seconds * 1000, key="auto-refresh")

if all([account_sid, auth_token, GROQ_API_KEY, conversation_sid]):
    os.environ["GROQ_API_KEY"] = GROQ_API_KEY

    @st.cache_data(show_spinner=False)
    def setup_knowledge_base():
        folder_path = "docs"
        all_text = ""
        try:
            for file in os.listdir(folder_path):
                if file.endswith(".pdf"):
                    all_text += extract_text_from_pdf(os.path.join(folder_path, file)) + "\n"
                elif file.endswith((".docx", ".doc")):
                    all_text += extract_text_from_docx(os.path.join(folder_path, file)) + "\n"
            tokenizer = AutoTokenizer.from_pretrained('bert-base-uncased')
            chunks = chunk_text(all_text, tokenizer)
            model = SentenceTransformer('all-mpnet-base-v2')
            embeddings = model.encode(chunks)
            dim = embeddings[0].shape[0]
            index = faiss.IndexFlatL2(dim)
            index.add(np.array(embeddings).astype('float32'))
            return index, model, chunks
        except Exception as e:
            st.error(f"Error setting up knowledge base: {e}")
            return None, None, None

    index, embedding_model, text_chunks = setup_knowledge_base()
    if index is None:
        st.stop()

    st.success("✅ Knowledge base ready. Monitoring WhatsApp...")

    with st.spinner("⏳ Checking for new WhatsApp messages..."):
        question, sender, msg_index = fetch_latest_incoming_message(account_sid, auth_token, conversation_sid)
        if question and msg_index > st.session_state.last_index:
            st.session_state.last_index = msg_index
            st.info(f"📥 New Question from {sender}:\n\n> {question}")
            relevant_chunks = retrieve_chunks(question, index, embedding_model, text_chunks)
            context = "\n\n".join(relevant_chunks)
            answer = generate_answer_with_groq(question, context)
            send_twilio_message(account_sid, auth_token, conversation_sid, answer)
            st.success("📤 Answer sent via WhatsApp!")
            st.markdown(f"### ✨ Answer:\n\n{answer}")
        else:
            st.caption("✅ No new message yet. Waiting for refresh...")
else:
    st.warning("❗ Please provide all required credentials and conversation SID.")